Manufacture of articles of footwear

ABSTRACT

A process for the manufacture of an article of footwear comprising the steps of joining a sole to an upper of rough material to which the sole can be directly joined without further processing, and applying to the part of the upper which is not covered by the sole in the finished article at least one covering layer. The sole can first be joined to the upper, e.g., by injection moulding, and the covering layer subsequently applied, or the covering layer can first be applied to the upper leaving uncovered the lower edge region to which the sole is to be joined and the sole then joined to this region.

United States Patent Schwab et al.

[54] MANUFACTURE OF ARTICLES OF FOOTWEAR [72] Inventors: Johann Schwab; Kurt Biichel, both of Vienna; Otto Eder, Ternitz; Wladilnir Hascic, Vienna; Maria Enzersdorf, Vienna; Ludwig Marek, Vienna, all of Austria [451 Oct. 17,1972

2,956,313 [0/1960 Choice ..l2/l42 E 1,907,856 5/1933 Murphy ..l2/l42 E 3,425,075 2/1969 Murray 12/142 R Primary ExaminerPatrick D. Lawson Attorney-Werner W. Kleeman [57] ABSTRACT A process for the manufacture of an article of footwear comprising the steps of joining a sole to an upper of rough material to which the sole can be directly joined without further processing, and applying to the part of the upper which is not covered by the sole in the finished article at least one covering layer. The sole can first be joined to the upper, e.g., by injection moulding, and the covering layer subsequently applied, or the covering layer can first be applied to the upper leaving uncovered the lower edge region to which the sole is to be joined and the sole then joined to this region.

29 Claims, 8 Drawing Figures PATENTEDum 1 1 I972 3 6 98 O2 7 saw 101 4 1 MANUFACTURE or ARTICLES or FOOTWEAR The present invention relates'to the manufacture of articles of footwear, in which a sole is joined to an upper. For the sake of clarity, the invention will be described with reference to shoes but it is equally applicable to other articles of footwear.

In the manufacture of shoes of this kind, it is extremely advantageous, for economical reasons, to use an upper material which in the rough state and does not as yet fulfil the minimum requirements for'the upper of the finished article, but does so only after the application of at least one covering layer. Examples of rough upper material of this kind include, in particular, fallow leather and textiles. However, smooth types of leather from which the shoes are to be manufactured are also generally treated with sprayed lacquers, anilinedyes or the like. Rubber, and synthetic resinous materials which are to be joined, in particular byinjection moulding, directly to a lasted leather upper, adhere poorly to surfaces of the latter kind. It is therefore necessary that at least the lasted layer should either be roughened and/or provided with a chemical bonding agent. Both of these alternatives requires additional processes and gives rise to material costs. it is also true that it is difficult both in the roughening process, and also in the application of bonding agents, to exactly preserve the contours of the sole which is later injection moulded on.

Hitherto, this has been effected with the aid of a template, or by the lasted upper being placed on the mould and removed again which resulted in a mark on the upper part of the shoe where the roughening and/or the coating with bonding agents was effected.

it has already been proposed to provide special leather preparations which improve the bonding of the leather with a synthetic resin or rubber sole. Such methods require, however, a specific preliminary treatment of the leather for each soling material, and are unecomonical for this reason. Moreover, with preliminary preparations of this kind, the entire surface of the leather is made to adhere well, which, for example, in the case of the use of polyvinyl chloride as sole material, may mean coating the upper with a polyvinyl chloride/acetate which not only changes the character of the leather of the upper but also involves the danger of a later soiling of the upper, to which materials can readily adhere. Such good adherence is not, of course, desirable over the whole of the upper for efficiency in use.

For reasons of fashion, great importance is placed onthe visual impression made by the surface of leather or synthetic leather materials. Unfortunately, only little consideration can,therefore, be paid to the technical necessities stemming from the subsequent soling and the good adhesive properties of the leather surface which is necessary for this purpose.

The fact that hitherto, practically all leather and synthetic leather shoes have been soled by sticking or injection moulding after the sole area of the upper has been roughened and/or provided with a bonding coating, proves that today we are not yet in the position to provide a surface finish for shoe leather which simultaneously meets the desired fashion and visual requirements, gives optimum efficiency in use, and furthermore acts as bonding agent for the sole material. It is also true that, evenincases in which the sole material or the bonding agent would adhere sufficiently to the leather surface finish, the adhesion of the leather finish to the leather surface is itself frequently insufficient. This can result during subsequent wear in the sole becoming loose.

Moreover, the leather is conventionally manufactured not only with the surface finish necessary for use, but also always in different colors. For a shoe factory this means, on the one hand, keeping stocks of various colors, which is expensive, in order to meet the requirements of fashion, andon'the other hand, involves the danger of stocks of leather, and also shoes made therefrom, in unfashionable colors which can no longer be sold, being left over. I

The highert'o conventional method of finishing the upper material before the production of the upper of the shoe, insofar as the shoe which is produced therefrom must be further provided with a known lacquer finish (to be distinguished from the leather finish), also possesses the particular disadvantage that the manufacture of the uppers is "thereby rendered difficult. The rough upper material becomes stiff as a result of the coating, and, moreover, in the processing to form the upper, it is easily damaged, so that the finished shoe must be subjected to a subsequent further treatment.

According: to the invention, there is provided a process for the manufacture of an article of footwear comprising the steps of joining a sole to. an upper of rough material to which the sole can be directly joined without further processing, and applyingtothe part of the upper which is not covered by the sole in the finished article of least one covering layer. Following the application'of the covering layer, the finished upper can, in known manner also be provided with a lacquer finish. v T

In the manufacture of shoes by the process of the invention, the disadvantages pointed out above are substantially removed, since both the visual and the economic requirements can be taken into account to an optimum extent through the application of the coating on the finished upper, so that the necessity to keep large stocks is avoided, and a special preliminary treatment of the entire surface of the leather, which is unfavorable for soling, is not necessary. Moreover, those difficulties are also avoided which continually occur in a shoe factory, owing to the leather supplies of different batches or different origin not being uniform in their color tints and/or finish.

Upper material for suitable use in the process in accordance with the invention may be, for example, uncolored chrome or vegetable tanned leather, having the lowest possible fat content, e.g., so-called fallow leather.

If possible, the fat content of the leather should not exceed 5 percent, the types of leather hitherto known which have the lowest fat contents possess a fat content in the region of l to 3 percent. The good adhering property with regard to adhesive agents or moulded-on soling materials is drastically influenced for the worse by too high a fat content of the leather, since the fat contained in the leather diffuses onto the surface thereof and there forms a natural separating layer between the leather and the material which is to adhere thereupon,

in similar fashion to plasticized synthetic resin materials, but often only after an extended period of time. If, in the case of relatively smooth uncolored typesof leather, the fat content lies above 5 percent, it is convenient in many cases to rinse the turned-down lasted edge part of the upper which is to be joined to the soling material with a suitable solvent in order to avoid roughening.

If there are objections that, in spite of the use of uncolored leather with which there should indeed by good bonding between the surface of the leather and the soling material, and yet a sufficient bonding with the uppermost layer (epidermis) of. the leather cannot be expected, it is convenient to use a leather, the uppermost layer of which has been scraped away in known manner before its machining to form the upper.

The upper can, however, also be made from a leather or synthetic leather, the surface of which is mat or veloured. As'most soling materials and bonding agents adhere sufficiently well to rough leather and also to veloured synthetic leather, it is not necessary in the case of uppers of materials of this kind to roughen the lasted layer or other parts of the surface of the .upper material which come into contact with the sole.

In accordance with a further feature of the present invention, the upper may be made from a bound or unbound textile material, such as, for example, a fleece,

or a knitted or woven fabric or the like. In particular fabrics e.g., tricots consisting of wool, polyester, polyamide, cellulose wool, acrylic fibers and the like, are suitable owing to their elasticity. In general, the textile material is stretched by about 40 percent when being pulled over the last. For example, atricot with the following properties, can be used:

Yarn number Ne 36 (Nm 60) -l2- l7 meshes/cm Weight 170 190 grammes/m Resistance to tearing 29/ l 3 kg/Scm Total extension 70/240% If the material is woven or knitted, it must be sufficiently elastic to cling closely to the last. If an unbound material is to be used, which is frequently desirable on account of the better moisture absorption capacity produced at the inner side of theshoe, it is convenient to use the material in the form of a tube, possibly stitched. This permits the production of simple forms of shoe, but avoids stitching or quilting of the upper which would involve outlay in personnel and cost.

Foils can also be used, preferably having a tubular form which corresponds to the last. For such an application, shrinkable foils with a sufficiently high shrinking capacity can be used. Polyethylene (having a shrinking capacity of, for example, 15 40 percent) is particularly suitable. Shrinkable foils consisting of polyvinyl chloride or polypropylene can also be used,

however. The shrinking is produced by increasing the stretched state) of approximately 4 mm, a total extension of more than percent, preferably percent, and a resistance to'tearing of l-kg/cm, may be used.

In order to avoid the polyurethane foam layer sticking to the last should it penetrate the covering layer, and in order to simplify the drawing on of the tube, the last can be coated with a parting or or sliding agent.

The coating of the part of the upper produced from rough material not in contact with the sole in the finished shoe, can be effected after the sole is joined to the upper which is still capable of good adhesion over its whole surface. The finishingof the surface of the upper already provided with a sole can advantageously be effected by electrostatic'sprayJacquering, while the upper is still mounted on a metal last and on the mould for the sole. In this way, the lacquer can be confined to the upper, without too great 'a manual outlay, the

necessity for covering the sole is avoided. It has, however, been found to be convenient to apply the sole by injection moulding to the upper in a mould provided internallywith suitableparting means and subsequently to lacquer the upper after removal of the shoe from the mould. Traces of lacquer which may have reached the sole can then readily be removed because of the residual separating agent located there. a

To remove such traces, the sole can either be given a preliminary treatment in such a way that any possible layer of lacquer, finish or the like can easily be removed, e.g., by pulling off a membrane intentionally formed on the surface of the; sole from a suitable synthetic resinous material, or can be treated by means of brushes. In order to achieve fashionable effects, an antique lacquer,for example, can also be applied to the sole, in particular to the cut edge. lf the lacquering of the upper is effected while the shoe is still on the mould, it is advantageous to provide the parts which may possibly come into contact with the lacquer or the like and which adjoin the lasted shoe, with suitable synthetic resin material, e.g., acetyl cellulose or polyvinyl alcohol, or with self-adhesive crepe strips.

It is also possible, however, first to provide the upper manufactured from rough upper material witha coat hydrogen atoms. Polyurethane elastomers which are capable of being dipped on or sprayed can be used as the covering layer preferably having a polyester base, or a polyurethane coating material. The latter can be rendered capable of coating bymeans of suitable solvents e.g., dimethylforrnamide, ethyl acetate, or tetrahydrofurane, and applied to the upper. Moreover leather lacquers or synthetic resin coating dyes which 4 are known per se can be used, such as, for example,

After the application of such'foils tothelast, they are sion properties towardsfthe covering layer. For example, a polyesterurethane foam of thickness (in the unwettable polymer solutions for transparent or pigmented textile coatings.

If particular designsarere'quired on the upper, these can be produced, for example,-in a'polyurethane coating, by processing the coating at a raised temperature. A special design can alsobe obtained by subsequent to provide the shoes or the upper at the point of wear,

such as, for example, at the heels, ankles, and/or toe areas with a particularly thick layer, which can, for example, be obtained'in spraying by allowingalonger dwell period of dwell of the jet in such areas. Moreover the entire shoe can also be strengthened by applying a further coating.

The entire shoe, after coating the sole with a separating agent can be submerged in a suitable solution, whereafter the sole is cleaned'by brushes or thelike. Suitable solutions are, for example, polyvinyl chloride plastisols or known lacquer solutions. The separating agent can be a paraffin or a paraffin wax paste; silicone compounds can also be used;

The invention will now be further described wit reference to the drawings, in which:

FIG. 1 is a side view of a last carrying one form of upper for use in a process according to the invention;

FIG. 2 is a side view of a last carrying another form of upper for use in a process according to the invention;

FIG. 3 is a plan view from below of a further upper for use in a process according to the invention;

FIG. 4 is a side view of a last carrying the upper of FIG. 3;

FIG. 5 is an end sectional view of a last carrying a shoe upper and sole in use in a process in accordance with the invention;

FIG. 6 is a similar view of last and mould in use in a process according to the invention;

FIG. 7 is a side view of a last carrying yet another upper for use in a process according to the invention; and

FIG. 8 is a side view of a last carrying a further upper for use in a process according to the invention.

In the figures, corresponding parts are indicated by the same reference numeral.

In the upper illustrated in FIG. 1, a last I is covered in the longitudinal direction with a substantiallytubular, highly elastic textile, or synthetic resinous material 2 which clings closely to the last owing to its elasticity. In the area of the toe of the last 3 and the heel section 4, the textile material is sewn together by means of horizontal seams 5 and 6, after which the sections 7 and 8 which project overthe last are turned downwards in the direction of the arrows 9 and 10. The seams 5 andf6 can be dispensed with, if desired; the sections 7 and 8 are then turned down and secured to the sole section, for example, by bonding, heat melting, sticking, or the like. Thus an unfinished upper is obtained, onto which a sole can be moulded. The coating of the upper part of the shoe can take place after or before the cutting out of the opening for the ankle section of the foot.

In the upper illustrated in FIG. 2, a'tube-shaped textile material 2 is again drawn over the last and is sewn and turned at the toe section of the last 3, as in FIG. 1. At the heel section 4, the textile material 2 is sewn together by a seam 11 which is essentially perpendicular and extends along the contour of the heel, andthe overhanging material is turned sideways in the direction of the arrow 12.

In the upper shown in FIG. 7, the textile material 12 is cut to size on the bias, sothat after it has been drawn over the last 1 it lies with the cut edges 29 and 30 para]- lel to the sole or ankle part, the cut edge- 29 forming the ankle opening. 7

- In the upperof FIG. 8; a textile material 2which has been drawn on to the last 1 is sewn over the heel. by a perpendicular seam.3l and at the instep through an inclined seam 32.

However, a textile piece can also be directly produced in stocking form and then drawn over the last. This upperis used in particular when because of an extreme design of the last, a tube which has been drawn over it is no longerin contact with all sections of the last.

FIGS. 3 and 4 show a last l over which an unfinished upper consisting of leather-type material is drawn. This unfinished upper consists to two sections 13, applied to the last on the right and left sides respectively and which are sewn .together by a seam 14in the instep and toe section and by a seam 15 in the heel'section. The parts l3-are, moreover, sewn to an inner sole 18 by seams 16 and 17, as shown in FIG. 3. In a particular design of the shoe upper, morethan two suchsections can also be sewn together in a manner known per se.

FIG. 5 shows a metal last 1 on which the upper 19 of a shoe has been drawn, the upper being provided with an inner sole 20, and onto which an outer sole 21 has been moulded. The last land a spray. nozzle 22 are connected to an electrostatic voltage source 23. In order to avoid coating of the outer sole 21 during the spraying process, and to direct the spray mist 24 exactly onto the part of the upper which is to be coated, the last 1' is provided with an insulating layer 25 in its bottom which prevents the electrostatic charging of the sole. section 21. By a special design of the insulating layer25, the electrostatic charge on the upper part of the shoe can be. such, that a stronger electrostatic charge is effected at the uppermost regions, so that a continuous shading in the color tone from below upwards is produced in the lacquering process.

FIG. 6 shows a last I carrying an upper 19, after the sole. 21 has been produced by injection moulding in a mould 26. The surface 27 of the mould 26 is covered with a foil 28, which prevents the surface 27 becoming soiled by the spraying means 24 during the spraying process. In place of the foil 28, the surface can, however, also be coated with a parting means, or can have a simply detachable coating. Dependent on the mould lips 33, which are applied between the sole21 and the upper 19, a narrow strip of the upper 19 adjacent to the sole 21 is not sprayed. This can be coated with a narrow brush after removal of the shoe from the mould. A narrow wheel can also be used, however, the peripheral edge of which is. covered with pigment and which is rolled over the section to be coated.

As previously mentioned, the lower edge portion of the upper can also be covered with a template during the coating operation, to which edge portion the sole, e.g., a polyurethane sole, is only subsequently joined.

It should be noted that the coating in accordance with the invention has nothing to do with the conventional application of a lacquer finish, which-is conven-' tionally sprayed onto finished shoes before they leave I the factory. The coating proposed in: accordance with l. A process for the manufacture of an article of footwear comprising the steps of forming a shaped upper of at least a partially unfinished material, said upper having a body portion of predetermined configuration, and a lower portion which is unfinished for receiving a sole directly without further conditioning, joining a sole directly to said lower portion of said upper without further processing, and applying to the part of the upper which is not covered by the sole in the finished article at least one covering layer for finishing said footwear.

2. A process as claimed in claim 1, wherein the sole is first joined to the upper and said part of the upper is subsequently provided with said covering layer or layers.

3. A process as claimed in claim 2, wherein the sole is joined to the upper by injection moulding in a mould provided internally with suitable parting means, whereafter the article is removed from the mould and said covering layer or layers applied, any traces of said layer or layers present on the sole being subsequently removed.

4. A processfor the manufacture of an article of footwear comprising the steps of first joining a sole to an upper of rough material by injection moulding, said mould provided on its innersurface with a parting layer, wherein said part of the upper not covered by the sole is provided with at least one covering layer in the mould, after the injection moulding of the sole, whereafter the articleis removed from the mould and covered with a layer in the region between the sole and the upper. j

5. A' process as claimed in claim 2, wherein after the sole has been joined to the upper, the article is immersed in a coating solution.

6. A process as claimed in claim 5 wherein prior to immersion, the sole is coated with a parting agent, whereby it can subsequently be cleansed of any adhering remnants of the coating solution.

7. A process as claimed in claim 1, wherein the upper with the exception of the lower edge region or lasted layer is first coated with said layer or layers, and the sole is subsequently joined to the uncoated part of the upper.

8. A process as claimed in claim 7, wherein during the coating of the upper, preferably on a last, the lower edge region of the upper or pinched layer, is covered by a template.

9. A process as claimed in claim 1 wherein said layer or layers is or are applied by electrostatic spray lacquering, while the upper is still located on a metal last and, if desired, on the mould for the sole.

l0. A,process as claimed in claim 1 wherein said upper is produced from a foamed material.

upper is of fallow leather.

13. A process as claimed in claim 11 wherein the uppermost layer of the leather is scraped away before the leather is processed to form said upper.

14. A process as claimed in claim .1 wherein said upper is of a material'having a mat or roughened surface.

15. A process as claimed in claim 1 wherein said u ri of s ntheticle t er.

g f A pr cess as c aiined in claim 1 wherein said upper is made of a textile material. 7

17. A process as claimed in claim 16 wherein said textile material is a tricot material.

18. A process as claimed in claim l6wherein said textile material has a tubular form.

19'. A process as claimed in claim 18, wherein said tube is sewn off or welded at the instep area in inclined fashion. r

20. A process as claimed in claim 1 wherein said upper is produced from a synthetic foil.

21. A process as claimed in claim 20 wherein said foil is a chrinkable foil.

22. A process as claimed in claim 20 wherein said foil is perforated.

23. A process as claimed in claim 20 wherein said synthetic foil is of tubular form.

24. A process as claimed in claim 23 wherein said tube is sewn off or welded at the instep area in inclined fashion.

25. A process asclaimed' inclaim 1, wherein said 26. A process as claimed in claim 25 wherein said foamed material is a polyurethane foam.

27. A process for the manufacture of an article of footwear comprising the steps of first coating an upper of rough material, with the exception of the lower edge portion of said upper, with at least one layer and subsequently joining a sole to the uncoated part of the upper, said lower edge portion of said upper being covered by a template during coating of the upper.

28. A process for the manufacture of an article of footwear comprising the steps of joining a sole to an layer is produced from a polyurethane-forming rea'cupper of rough material to which the sole can be directly joined without further processing, and applying to the part of the upper which is not covered by the sole in the finished article at least one covering layer, said upper being made from a textile material of tubular configuration.

29. A process for the manufacture of an article of footwear comprising the steps of joining a sole to an upper of rough material to which the sole can be directly joined without further processing, and applying to the part of the upper which is not covered by the sole in the finished article at least one covering layer, said upper being fabricated from a synthetic foil of tubular configuration, said tube being secured at the instep area in inclined fashion. 

1. A process for the manufacture of an article of footwear comprising the steps of forming a shaped upper of at least a partially unfinished material, said upper having a body portion of predetermined configuration, and a lower portion which is unfinished for receiving a sole directly without further conditioning, joining a sole directly to said lower portion of said upper without further processing, and applying to the part of the upper which is not covered by the sole in the finished article at least one covering layer for finishing said footwear.
 2. A process as claimed in claim 1, wherein the sole is first joined to the upper and said part of the upper is subsequently provided with said covering layer or layers.
 3. A process as claimed in claim 2, wherein the sole is joined to the upper by injection moulding in a mould provided internally with suitable parting means, whereafter the article is removed from the mould and said covering layer or layers applied, any traces of said layer or layers present on the sole being subsequently removed.
 4. A process for the manufacture of an article of footwear comprising the steps of first joining a sole to an upper of rough material by injection moulding, said mould provided on its inner surface with a parting layer, wherein said part of the upper not covered by the sole is provided with at least one covering layer in the mould, after the injection moulding of the sole, whereafter the article is removed from the mould and covered with a layer in the region between the sole and the upper.
 5. A process as claimed in claim 2, wherein after the sole has been joined to the upper, the article is immersed in a coating solution.
 6. A process as claimed in claim 5 wherein prior to immersion, the sole is coated with a parting agent, whereby it can subsequently be cleansed of any adhering remnants of the coating solution.
 7. A process as claimed in claim 1, wherein the upper with the exception of the lower edge region or lasted layer is first coated with said layer or layers, and the sole is subsequently joined to the uncoated part of the upper.
 8. A process as claimed in claim 7, wherein during the coating of the upper, preferably on a last, the lower edge region of the upper or pinched layer, is covered by a template.
 9. A process as claimed in claim 1 wherein said layer or layers Is or are applied by electrostatic spray lacquering, while the upper is still located on a metal last and, if desired, on the mould for the sole.
 10. A process as claimed in claim 1 wherein said layer is produced from a polyurethane-forming reaction mixture.
 11. A process as claimed in claim 1 wherein said upper part of the shoe is of uncolored leather.
 12. A process as claimed in claim 11 wherein said upper is of fallow leather.
 13. A process as claimed in claim 11 wherein the uppermost layer of the leather is scraped away before the leather is processed to form said upper.
 14. A process as claimed in claim 1 wherein said upper is of a material having a mat or roughened surface.
 15. A process as claimed in claim 1 wherein said upper is of synthetic leather.
 16. A process as claimed in claim 1 wherein said upper is made of a textile material.
 17. A process as claimed in claim 16 wherein said textile material is a tricot material.
 18. A process as claimed in claim 16 wherein said textile material has a tubular form.
 19. A process as claimed in claim 18, wherein said tube is sewn off or welded at the instep area in inclined fashion.
 20. A process as claimed in claim 1 wherein said upper is produced from a synthetic foil.
 21. A process as claimed in claim 20 wherein said foil is a chrinkable foil.
 22. A process as claimed in claim 20 wherein said foil is perforated.
 23. A process as claimed in claim 20 wherein said synthetic foil is of tubular form.
 24. A process as claimed in claim 23 wherein said tube is sewn off or welded at the instep area in inclined fashion.
 25. A process as claimed in claim 1, wherein said upper is produced from a foamed material.
 26. A process as claimed in claim 25 wherein said foamed material is a polyurethane foam.
 27. A process for the manufacture of an article of footwear comprising the steps of first coating an upper of rough material, with the exception of the lower edge portion of said upper, with at least one layer and subsequently joining a sole to the uncoated part of the upper, said lower edge portion of said upper being covered by a template during coating of the upper.
 28. A process for the manufacture of an article of footwear comprising the steps of joining a sole to an upper of rough material to which the sole can be directly joined without further processing, and applying to the part of the upper which is not covered by the sole in the finished article at least one covering layer, said upper being made from a textile material of tubular configuration.
 29. A process for the manufacture of an article of footwear comprising the steps of joining a sole to an upper of rough material to which the sole can be directly joined without further processing, and applying to the part of the upper which is not covered by the sole in the finished article at least one covering layer, said upper being fabricated from a synthetic foil of tubular configuration, said tube being secured at the instep area in inclined fashion. 